Field of the Invention
The present invention relates to the automatic transmission of a vehicle.
Description of the Related Art
As an automatic transmission, a so-called dual clutch transmission is known. The dual clutch transmission includes two transmission mechanisms that implement different gear ratios, and connects/disconnects the two transmission mechanisms to/from a driving source such as an internal combustion engine, thereby suppressing interruption of power transmission to the drive wheels at the time of gear change. Japanese Patent No. 5081215 discloses, in a dual clutch transmission, intentionally putting a vehicle in two speed gears for parking lock, thereby interlocking the transmission to maintain the stop state of the vehicle.
One of the challenges of the dual clutch transmission is to prevent a vehicle that has stopped on a climbing hill from moving back. To solve this problem, intentional interlocking as in Japanese Patent No. 5081215 can be considered. However, since two speed gears are put in gear, the operation time may be long.